Validation of living donor nephrectomy codes

Background — Use of administrative data for outcomes assessment in living kidney donors is increasing given the rarity of complications and challenges with loss to follow-up.

Objective — To assess the validity of living donor nephrectomy in health care administrative databases compared with the reference standard of manual chart review.

Design — Retrospective cohort study.

Setting — 5 major transplant centers in Ontario, Canada.

Patients — Living kidney donors between 2003 and 2010.

Measurements — Sensitivity and positive predictive value (PPV).

Methods — Using administrative databases, we conducted a retrospective study to determine the validity of diagnostic and procedural codes for living donor nephrectomies. The reference standard was living donor nephrectomies identified through the province's tissue and organ procurement agency, with verification by manual chart review. Operating characteristics (sensitivity and PPV) of various algorithms using diagnostic, procedural, and physician billing codes were calculated.

Results — During the study period, there were a total of 1199 living donor nephrectomies. Overall, the best algorithm for identifying living kidney donors was the presence of 1 diagnostic code for kidney donor (ICD-10 Z52.4) and 1 procedural code for kidney procurement/excision (1PC58, 1PC89, 1PC91). Compared with the reference standard, this algorithm had a sensitivity of 97% and a PPV of 90%. The diagnostic and procedural codes performed better than the physician billing codes (sensitivity 60%, PPV 78%).

Limitations — The donor chart review and validation study was performed in Ontario and may not be generalizable to other regions.

Conclusions — An algorithm consisting of 1 diagnostic and 1 procedural code can be reliably used to conduct health services research that requires the accurate determination of living kidney donors at the population level.